Compressed-Air Supply Device for a Utility Vehicle and Method for Operating a Compressed-Air Supply Device

ABSTRACT

A compressed-air supply device for a utility vehicle includes a valve device, which, when in a first, energized switching state, deaerates the control inlet of a compressor coupled to the energy-saving control outlet and blocks a supply path to the second valve device, and when in a second, de-energized switching state, aerates the control inlet of the compressor coupled to the energy-saving control outlet and opens up the supply path to the second valve. The compressor can be switched into an energy-saving state by aeration of the control inlet.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a compressed-air supply device for a utility vehicle and a method for operating a compressed-air supply device.

Compressed-air supply devices fulfill numerous tasks in utility vehicles. These include in particular the supply of the brake system and other compressed air consumers with dried cleaned compressed air, the exercise of a multi-circuit protection valve function for protecting various consumer circuits against each other and for ensuring a certain filling sequence and the provision of a pressure regulator function. The compressed air consumed by the compressed air consumers is primarily provided by a compressor, which is generally driven by the internal combustion engine of the utility vehicle. With numerous systems the compressor can be changed into an energy-saving state, either by separating a coupling via which the compressor can be coupled to the internal combustion engine, or by pneumatically controlling a compressor control input in order to change the compressor into an idling state. Such energy-saving measures can also be supported by carrying out the operating processes in the compressed-air supply device such that compressed air once generated is not lost unnecessarily. Here it is to be noted that a certain loss of compressed air is inevitable, because the filter unit of the compressed-air supply device has to be repeatedly regenerated. For this purpose dry compressed air is passed from the compressed air containers connected to the compressed-air supply devices through the filter unit in a direction that is opposite to the delivery direction. The air flowing through the filter unit at least partly absorbs the moisture in the filter unit in order to then flow into the open via the drain valve of the compressed-air supply device.

In certain systems of the prior art it is provided to couple the energy-saving state to the opening of the drain valve, i.e. whenever the compressor is changed into an energy-saving state the drain valve is also opened, so that thereby an unnecessary loss of pressure occurs in the entire delivery line upstream of a non-return valve facing the consumers and being disposed downstream of the filter unit.

EP 1 318 936 B1 describes a compressed-air supply device that is equipped with a regeneration function and an energy-saving output for changing a compressor into an idling state. Two solenoid valves are provided that implement said functions. It is thereby provided that the opening of the regeneration air path is coupled to the opening of the drain valve. In this way the compressed air is only lost from the volume between the drain valve and a non-return valve disposed downstream of the filter unit and facing the consumers if this is inevitable because of the required regeneration.

DE 10 2007 009 767 B4 discloses a compressed-air supply device with a compressed air input that can be coupled to a compressor, a filter unit coupled to the compressed air input by means of a delivery line, a drain valve coupled to a drain output and the delivery line, an energy-saving control output that can be coupled to a control input of the compressor, a first valve device and a second valve device, wherein the drain valve, the energy-saving control output and the regeneration of the filter unit can be controlled by means of the valve devices, wherein the energy-saving control output can be controlled by the first valve device and the drain valve and the regeneration of the filter unit can be controlled by the second valve device and that the second valve device can be supplied with compressed air by the first valve device. In that the drain valve is only changed into its opened state on initiating the regeneration function, it can be ensured that the volume of compressed air in the delivery line upstream of the non-return valve facing the consumers is only lost if this is inevitable because of the required operating states. It can thus be ensured that when operating the compressed-air supply device only that pressure is lost that is necessary for implementing a regeneration function.

The object of the invention is to provide a compressed-air supply device with changed functionality compared to the prior art.

This object is achieved with a compressed-air supply device, and a method of operating same, for a utility vehicle with a compressed air input that can be coupled to a compressor, a filter unit coupled to the compressed air input via a delivery line, a drain valve coupled to a drain output and the delivery line, an energy-saving control output that can be coupled to a control input of the compressor, and a first valve device and a second valve device. The drain valve, the energy-saving control output and the regeneration of the filter unit can be controlled by the valve devices, wherein the energy-saving control output can be controlled by the first valve device and the drain valve and the regeneration of the filter unit can be controlled via the second valve device. The second valve device can be supplied with compressed air by the first valve device, wherein the first valve device deaerates the control input of a compressor coupled to the energy-saving control output and blocks a supply path to the second valve device in a first switching state and in a second switching state aerates the control input of the compressor coupled to the energy-saving control output and opens the supply path to the second valve. The compressor can be changed into an energy-saving state by aerating the control input, wherein the first valve device is energized in its first switching state and is de-energized in its second switching state.

The invention builds on the compressed-air supply device according to DE 10 2007 009 767 B4 in that the first valve device is energized in its first switching state and is de-energized in its second switching state.

Advantageously, it is provided that the first valve device is a 3/2-way valve, which in a first switching state deaerates the control input of a compressor coupled to the energy-saving output and blocks a supply path to the second valve device and in a second switching state aerates the control input of the compressor coupled to the energy-saving control output and opens the supply path to the second valve. The compressor can be changed into an energy-saving state by aerating the control input. The second valve device is thus only supplied with compressed air if the compressor is changed into its energy-saving state. This is advantageous because the second valve device only has to be active in relation to the other functions of the compressed-air supply device.

It can be provided that the second valve device is a 3/2-way valve which in a first switching state deaerates a control input of the drain valve and blocks a regeneration path and in a second switching state aerates the control input of the drain valve and opens a regeneration path. The drain valve can be changed into an opened state by aerating the control input. In the non-driven state the drain valve is thus closed. Opening only takes place if it is unavoidable because of the regeneration. In that the second valve device is configured as a 3/2-way valve the same as the first valve device, the valve devices can be implemented with the same construction.

It can however also be advantageous that the second valve device is a 2/2-way valve, which in a first switching state deaerates a control input of the drain valve and blocks a regeneration path and in a second switching state aerates the control input of the drain valve and opens a regeneration path. The drain valve can be changed into an opened state by aerating the control input. With regard to providing the functions “opening the regeneration path” and “aerating the drain valve control input”, a 2/2-way valve is sufficient, so that overall a 3/2-way valve and a 2/2-way valve suffice for the compressed-air supply device according to the invention with regard to the present regeneration and energy-saving concept.

By the provision of two valve devices, each with two switching states, there are in all four possible operating states, but because of the supply of the second valve device by the first valve device there are only three relevant operating states, wherein it is provided that in a first operating state of the compressed-air supply device the first valve device adopts its first switching state and the second valve device adopts its first switching state, resulting in a load operating state. The regeneration path is closed, the compressor is in its load phase and the drain valve is closed.

It is further provided that in a second operating state of the compressed-air supply device the first valve device adopts its second switching state and the second valve device adopts its second switching state, resulting in a regeneration operating state. The regeneration air path is opened, the drain valve is opened and the compressor is in its idling phase.

It is further provided that in a third operating state of the compressed-air supply device the first valve device adopts its second switching state and the second valve device adopts its first switching state, resulting in a blocking operating state. The compressor is in its idling phase and the regeneration air path, i.e. a path that bypasses the non-return valve following the filter unit and facing the consumer circuits, is opened. The drain valve is closed, however, so that an outflow of air is prevented.

It is particularly advantageous that an electronic control unit is provided and that the valve devices are solenoid valves. This allows the different operating states of the compressed-air supply device to be adopted based on intelligent calculations, wherein in particular numerous information items relating to the utility vehicle can be taken into account.

The invention builds on the generic method according to DE 10 2007 009 767 B4 in that the first valve device is energized in its first switching state and is de-energized in its second switching state. This enables the advantages and features of the compressed-air supply device according to the invention to be implemented within the framework of a method. This also applies to the particularly preferred embodiments of the method according to the invention given below.

This is particularly characterized in that the first valve device is a 3/2-way valve.

It can also advantageously be provided that the second valve device is a 3/2-way valve that deaerates a control input of the drain valve and blocks a regeneration path in a first switching state and in a second switching state aerates the control input of the drain valve and opens a regeneration path, and that the drain valve is changed into an open state by aerating the control input.

It can also be provided that the second valve device is a 2/2-way valve that deaerates a control input of the drain valve and blocks a regeneration path in a first switching state and in a second switching state aerates the control input of the drain and opens a regeneration path, and that the drain valve is changed into an open state by aerating the control input.

The method according to the invention is developed in an advantageous manner in that in a first operating state of the compressed-air supply device the first valve device adopts its first switching state and the second valve device adopts its first switching state, resulting in a load operating state.

It is further provided that in a second operating state of the compressed-air supply device the first valve device adopts its second switching state and the second valve device adopts its second switching state, resulting in a regeneration operating state.

It is preferred that in a third operating state of the compressed-air supply device the first valve device adopts its second switching state and the second valve device adopts its first switching state, resulting in a blocking operating state.

Advantageously, it is provided that the valve devices are controlled by an electronic control unit.

The invention will now be explained by way of example using particularly preferred embodiments with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic partial illustration of a compressed-air supply device of the prior art according to DE 10 2007 009 767 B4;

FIG. 2 shows a schematic axial section through a first embodiment of a valve device and components connected thereto;

FIG. 3 shows a schematic axial section through a second embodiment of a valve device and components connected thereto; and

FIG. 4 shows a schematic partial illustration of a compressed-air supply device according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic partial illustration of a compressed-air supply device of the prior art according to DE 10 2007 009 767 B4. The compressed-air supply device 10 contains an electronic control unit 12. Two 3/2-way solenoid valves 16, 18 can be controlled by the electronic control unit 12. Other components, e.g. a heating component, pressure sensors and other solenoid valves, which can be provided in combination with the electronic control unit 12, are not illustrated. The compressed-air supply device has a compressed air input 26 that can be coupled to a compressor and a drain output 24. A drain valve 20 is disposed between the compressed air input 26 and the drain output 24. A filter unit 14 is also connected to the compressed air input 26. The compressed air delivered to the compressed air input 26 is passed to the consumer circuits via said filter unit 14, wherein a non-return valve 42 is provided on said path, which prevents reverse flow of compressed air from the consumer circuits. A compressed air container 62 is illustrated to represent the consumer circuits, wherein the filling of the compressed air container 62 from the line coupled to the non-return valve 42 generally takes place via a multi-circuit protection valve device incorporated in the compressed-air supply device and not shown here. The compressed-air supply device 10 also comprises an energy-saving control output 28, to which a control input of the compressor coupled to the compressed air input 26 can be connected.

The solenoid valve 16 is connected to a line 30 that leads to the compressed air container 62 and which is thus under operating brake pressure under normal operating conditions. Another line 32 is connected to the solenoid valve 16, wherein this is connected to the drain output 24. The third connection of the solenoid valve 16 is connected to the energy-saving control output 28 and via a supply path 36 to a first connection of the second solenoid valve 18. A second connection of the second solenoid valve 18 is connected to the drain output 24 via a line 40. The third connection of the solenoid valve 18 is connected via a non-return valve 44 and a choke 38 to a section of the delivery line 46, which is disposed downstream of the filter unit 14 and upstream relative to the non-return valve 42 in relation to the flow direction of the compressed air during the delivery phase. Furthermore, the third connection of the solenoid valve 18 is connected to the control input 34 of the drain valve 20.

If the solenoid valves 16, 18 are de-energized, they adopt their switching state illustrated in the lower part of the valve symbol, whilst the solenoid valves 16, 18 implement the switching state illustrated in the upper part of the valve symbol in the energized state.

If both solenoid valves 16, 18 are de-energized, then the control input of the compressor coupled to the energy-saving control output 28 is deaerated via the line 32 and the drain output 24. The regeneration air path is “doubly blocked”, because on the one hand, because of the de-energized position of the solenoid valve 16, no supply pressure is fed to the solenoid valve 18, and because on the other hand also the solenoid valve 18 causes blocking of the regeneration air path. Because of the lack of supply to the solenoid valve 18 via the supply path 36, a changeover of the second valve device 18 would not be effective.

If both solenoid valves 16, 18 are energized, aeration of the control input of the compressor takes place via the energy-saving control output 28, so that the compressor is changed into its idling state; this is achieved by energizing the valve device 16. By energizing the valve device 18 the control input 34 of the drain valve 20 is operated, so that the drain valve 20 changes over. At the same time the regeneration air path is opened, i.e. a connection is made between the compressed air container 62 and the drain output 24 via the first valve device 16, the second valve device 18, the non-return valve 44, the choke 38, the delivery line section 46, the filter unit 14 and the drain valve 20.

If the first solenoid valve 16 is energized while the second solenoid valve 18 is de-energized the compressor is switched into an idling state by aerating its control input via the energy-saving control output 28. However no regeneration takes place because the regeneration air path is blocked by the solenoid valve 18 and the drain valve 20. A changeover of the compressor into its idling state therefore need not necessarily be accompanied by regeneration, so that the volume of compressed air flowing out during the regeneration is not lost.

Based on the present invention, unnecessary emptying of the line volume between the non-return valve 42 and the drain valve 20 outside the regeneration phases is avoided.

FIG. 2 shows a schematic axial section through a first embodiment of a valve unit, which can be used advantageously in combination with the present invention. With the drain valve 20′ illustrated here, the drain function and the provision of a regeneration air path can be combined in a particular manner. In the illustrated switching state a delivery of compressed air from the compressor 22 into the drain valve 20′ can take place. The compressed air thus delivered flows through a valve chamber 60 of the drain valve 20′ and from there via the filter unit 14 and the non-return valve 44 to the consumers, which are symbolized here by a compressed air container 62, wherein in addition a multi-circuit protection valve device can of course be interposed. The system pressure present downstream of the non-return valve 44 can then be used by the first valve device 16 and the second valve device 18′ to provide control pressures. The valve device 16 thereby undertakes the supply of the valve device 18′ and the control of a control input 48 provided on the compressor 22. The drain valve unit 20′ comprises a control piston. A control piston end plate 66 separates a control chamber 68 connected to the second electrically controllable valve device 18′ from a return chamber 70 by means of a seal 84 that interacts with a valve housing 72. The return chamber 70 contains a (not illustrated) vent opening in order to allow unhindered displacement of the control piston 64. The control piston 64 also comprises a constriction 74, wherein the control piston is sealed against the adjacent spaces enclosing the control piston 64 on both sides of the constriction 74 by means of seals 86, 88.

The valve chamber enclosing the constriction 74, as the first regeneration valve chamber 98, is thus sealed against the return chamber 70 of the control piston plate 66 and against a second regeneration valve chamber 76. Said second regeneration valve chamber 76 is separated from the already mentioned valve chamber 60 by means of a further seal 90. The valve chamber 60 is delimited by a valve plate 78, which is pressed against a valve seat by a spring 80. In this way the valve plate 78 seals the valve chamber 60 against an outlet 82.

In all the drain valve 20′ thus comprises five seals, namely the valve seat that interacts with the valve plate 78 and the seals 84, 86, 88, 90 implemented as O-Rings, which interact with the valve housing 72 and seal the control chamber 68, the return chamber 70, the first regeneration valve chamber 98, the second regeneration valve chamber 76 and the valve chamber 60 against each other.

In the switching state illustrated in FIG. 2 the second electrically controllable valve device 18′ deaerates the control chamber 68. Said deaeration takes place either directly, wherein the valve device 18′ is advantageously designed as a 3/2-way valve, or it is possible that the deaeration takes place via the supply line 36 and the first valve device 16. It is then sufficient if the second valve device 18′ is a 2/2-way valve. The valve plate 78 seals the valve chamber 60 against the outlet 82 and the seal 88 seals the region downstream of the non-return valve 44, i.e. the compressed air consumer side, against the air path, which is provided with a choke 38, to the filter unit 14. If the second valve device 18′ is controlled with the first valve device 16 open, so that the control chamber 68 is aerated, this displaces the control piston 64. This causes the control piston to lift the valve plate 78 from the valve seat on the one hand, so that the valve chamber 60 is connected to the outlet 82, and on the other hand causes the space enclosing the constriction 74 to now provide a connection between the consumer side, i.e. in the region downstream of the non-return valve 44, and the filter unit 14. Because the outlet is open in this state, a return flow of compressed air from the consumer side can take place via the filter unit to the outlet. In this respect the drain valve 20′ combines the drain function with a 2/2-way valve function for the provision of a regeneration air path. According to the present exemplary embodiment, this 2/2-way valve function is implemented by a constriction.

FIG. 3 shows a schematic axial section through a second embodiment of a valve device and components connected thereto. The valve device illustrated in FIG. 3 differs from the valve device illustrated in FIG. 2 in that instead of a constriction 74 a channel 96 is provided. In the illustrated switching state both openings 100, 102 of the channel 96 lie within the first regeneration valve chamber 98, while by applying pressure to the control chamber 68 the control piston 64 is displaced such that the channel 96 connects both regeneration valve chambers 76, 98 together in order to complete a regeneration air path in this way.

FIG. 4 shows a schematic partial illustration of a compressed-air supply device according to the invention. In comparison to the compressed-air supply device of the prior art according to DE 10 2007 009 767 B4, here the connections of the first valve device 16 are differently allocated. Thus in the de-energized state of the valve device 16, the line 30 is connected to the energy-saving control output 28, which is thereby under pressure, while the line 32 leading to the drain output 24 is closed. In order to change the compressed-air supply device according to the invention into the load state with the compressor supplying, the valve device 16 must be energized, whereas according to the prior art the load state existed with the valve device 16 de-energized. The present valve device 16 wiring according to the invention has numerous effects on the switching logic of the system, especially in relation to the reaction of the system in the event of a power failure.

The features of the invention disclosed in the above description, in the figures and in the claims can be significant for the realization of the invention both individually and also in any combination.

REFERENCE CHARACTER LIST

-   10 compressed-air supply device -   12 control unit -   14 filter unit -   16 solenoid valve -   18 solenoid valve -   18′ valve device -   20 drain valve -   22 compressor -   24 drain output -   26 compressed air input -   28 energy-saving control output -   30 line -   32 line -   34 control input -   36 line -   38 choke -   40 line -   42 non-return valve -   44 non-return valve -   46 delivery line section -   48 control input -   60 valve chamber -   62 compressed air container -   64 control piston -   66 control piston plate -   68 control chamber -   70 return chamber -   72 valve housing -   74 constriction -   76 regeneration valve chamber -   78 valve plate -   80 spring -   82 drain outlet -   84 seal -   86 seal -   88 seal -   90 seal -   96 channel -   98 regeneration valve chamber -   100 opening -   102 opening 

1-16. (canceled)
 17. A compressed-air supply device for a utility vehicle equipped with a compressor, comprising: a compressed air input that is coupleable to the compressor; a filter unit coupled to the compressed air input via a delivery line; a drain valve coupled to a drain output and the delivery line; an energy-saving control output that is coupleable to a control input of the compressor; and a first valve device and a second valve device, wherein the drain valve, the energy-saving control output and regeneration of the filter unit are controllable by the first and second valve devices, the energy-saving control output is controllable via the first valve device and the drain valve and the regeneration of the filter unit are controllable via the second valve device, the second valve device is supplyable with compressed air by the first valve device, the first valve device deaerates the control input of the compressor coupled to the energy-saving control output and blocks a supply path to the second valve device in a first switching state, and in a second switching state aerates the control input of the compressor coupled to the energy-saving control output and opens the supply path to the second valve, the compressor is changeable into an energy-saving state by aerating the control input, and the first valve device is energized in its first switching state and is de-energized in its second switching state.
 18. The compressed-air supply device as claimed in claim 17, wherein the first valve device is a 3/2-way valve.
 19. The compressed-air supply device as claimed in claim 17, wherein the second valve device is a 3/2-way valve that deaerates a control input of the drain valve and blocks a regeneration path in a first switching state and in a second switching state aerates the control input of the drain valve and opens a regeneration path, and further wherein the drain valve is changeable into an opened state by aerating the control input.
 20. The compressed-air supply device as claimed in claim 17, wherein the second valve device is a 2/2-way valve that deaerates a control input of the drain valve and blocks a regeneration path in a first switching state and in a second switching state aerates the control input of the drain valve and opens a regeneration path, and the drain valve can be changed into an opened state by aerating the control input.
 21. The compressed-air supply device as claimed in claim 19, wherein in a first operating state of the compressed-air supply device the first valve device adopts its first switching state and the second valve device adopts its first switching state, resulting in a load operating state.
 22. The compressed-air supply device as claimed in claim 20, wherein in a first operating state of the compressed-air supply device the first valve device adopts its first switching state and the second valve device adopts its first switching state, resulting in a load operating state.
 23. The compressed-air supply device as claimed in claim 19, wherein in a second operating state of the compressed-air supply device the first valve device adopts its second switching state and the second valve device adopts its second switching state, resulting in a regeneration operating state.
 24. The compressed-air supply device as claimed in claim 20, wherein in a second operating state of the compressed-air supply device the first valve device adopts its second switching state and the second valve device adopts its second switching state, resulting in a regeneration operating state.
 25. The compressed-air supply device as claimed in claim 19, wherein in a third operating state of the compressed-air supply device the first valve device adopts its second switching state and the second valve device adopts its first switching state, resulting in a blocking operating state.
 26. The compressed-air supply device as claimed in claim 20, wherein in a third operating state of the compressed-air supply device the first valve device adopts its second switching state and the second valve device adopts its first switching state, resulting in a blocking operating state.
 27. The compressed-air supply device as claimed in claim 17, further comprising: an electronic control unit configured to control the compressed air supply device, wherein the valve first and second devices are solenoid valves.
 28. A method of operating a compressed-air supply device with a compressed air input coupleable to a compressor, a filter unit coupled to the compressed air input via a delivery line, a drain valve coupled to a drain output and the delivery line, an energy-saving control output that is coupleable to the control input of the compressor, a first valve device and a second valve device, the method comprising the acts of: controlling the drain valve, the energy-saving control output and the regeneration of the filter unit by the valve devices, wherein the energy-saving control output is controlled by the first valve device and the drain valve and the regeneration of the filter unit are controlled by the second valve device; supplying the second valve device with compressed air by the first valve device, wherein: the first valve device deaerates the control input of a compressor coupled to the energy-saving control output and blocks a supply path to the second valve device in a first switching state and in a second switching state aerates the control input of the compressor coupled to the energy-saving control output and opens the supply path to the second valve, and the compressor is changeable into an energy-saving state by aerating the control input, wherein the first valve device is energized in its first switching state and is de-energized in its second switching state.
 29. The method as claimed in claim 28, wherein the first valve device is a 3/2-way valve.
 30. The method as claimed in claim 28, wherein the second valve device is a 3/2-way valve that deaerates a control input of the drain valve and blocks a regeneration path in a first switching state and in a second switching state aerates the control input of the drain valve and opens a regeneration path, and further wherein the drain valve is changed into an opened state by aerating the control input.
 31. The method as claimed in claim 28, wherein the second valve device is a 2/2-way valve that deaerates a control input of the drain valve and blocks a regeneration path in a first switching state and in a second switching state aerates the control input of the drain valve and opens a regeneration path, and further wherein the drain valve can be changed into an opened state by aerating the control input.
 32. The method as claimed in claim 30, wherein in a first operating state of the compressed-air supply device the first valve device adopts its first switching state and the second valve device adopts its first switching state, resulting in a load operating state.
 33. The method as claimed in claim 31, wherein in a first operating state of the compressed-air supply device the first valve device adopts its first switching state and the second valve device adopts its first switching state, resulting in a load operating state.
 34. The method as claimed in claim 30, wherein in a second operating state of the compressed-air supply device the first valve device adopts its second switching state and the second valve device adopts its second switching state, resulting in a regeneration operating state.
 35. The method as claimed in claim 30, wherein in a third operating state of the compressed-air supply device the first valve device adopts its second switching state and the second valve device adopts its first switching state, resulting in a blocking operating state.
 36. The method as claimed in claim 28, wherein the valve devices are controlled by an electronic control unit. 